1. Field of the Invention
The present invention relates to an air pressure management device for a vehicle tire and a vehicle tire capable of outputting air pressure information.
2. Description of Related Art
In recent years, an insufficient tire pressure has been drawing attention as a cause of a traffic accident, and various proposals are made under a trend of mandatory installation of a tire pressure monitoring system (TPMS). For example, in Japanese Patent Application Laid-open No. 2008-86190, there is proposed an installation of a communication device, which is supplied with electric power for its operation by an electrostatic-induction type electric power generator employing an electret for generating electric power by vibrations of a vehicle, and which detects tire air pressure and internal tire temperature and outputs the detected tire air pressure and internal tire temperature through wireless communication, on the tire or a tire wheel of the vehicle. Moreover, Japanese Patent Application Laid-open No. 2009-33809 may be cited as another related technical document.
However, a practical air pressure management device for a tire and a practical vehicle tire capable of outputting air pressure information still have many problems to be overcome, including a problem with power supply inside the tire.